The present invention relates to a stabilizing support for opening- and closing-wedge osteotomies, particularly of the miniinvasive type for tibial and femoral osteotomies.
The practice of osteotomy, performed in particular at the distal epiphysis of the femur or at the proximal epiphysis of the tibia in order to modify the load conditions of the knee, is currently widely used and often is the most advisable solution when the patient's angle between the diaphyseal longitudinal axis of the femur and the longitudinal axis of the tibia is open medially or laterally at values that differ from those considered anatomically normal.
Stabilizing supports constituted by a plate for connecting, by means of screws, the two bone portions formed by the osteotomy rima are known. For better comprehension, reference should be made to FIGS. 1 and 2, which refer to a particular stabilizing support, disclosed in U.S. Pat. Nos. 5,620,448 and 5,749,875.
FIG. 1 is a perspective view of a detail of a stabilizing support 1 fixed to the proximal epiphysis of the tibia 2 by means of screws 2a and constituted by a plate 3 provided with a tooth 4 to be inserted in a osteotomy rima 5; such tooth, which has an upper face 6 and a lower face 7, is suitable to support the axial load that bears on the bone. FIG. 2 is instead a perspective view of such support.
Support 1 has a drawback linked to the shape of the tooth 4, which is preferably parallelepipedal and therefore does not ensure correct resting of opposite surfaces 8 and 9 formed by the rima 5, which is substantially wedge-shaped. The contact between the surfaces 8 and 9 and the tooth 4 in fact occurs only along points or segments (for example along the segment 10) and therefore is not distributed correctly on the upper face 6 and the lower face 7 of the tooth 4.
Accordingly, the screws 2a are loaded excessively by the weight of the body of the patient, causing wear and mechanical instability. Furthermore, the presence of the tooth 4 inserted in the osteotomy rima 5 prevents its correct and complete filling with any bone inserts; therefore, after the removal of the support, the bone portion affected by the rima might not be perfectly intact and might have insufficient mechanical strength.